This disclosure is in the field of electric power distribution. Disclosed embodiments are directed to rectifiers, rectifying power converters, and systems including such devices, capable of receiving power from various types of power sources.
The generation of electrical power from renewable energy sources such as solar, wind, water, and geothermal has become more popular in recent years. Solar and wind energy have become especially attractive in providing electrical power to loads near the generation site, such as at cellular telephone towers, telecommunication central offices, home or business locations that are independent from the electrical power grid, and the like. The electrical power generated by solar and wind-generated electrical power fluctuates over time (e.g., day vs. night for solar power), and in response to weather and other environmental conditions.
To reduce the expense of metered power from the AC grid and to reduce environmental impact, among other reasons, it is often desirable to use power from renewable sources such as solar cell arrays, wind-powered generators, and the like when that power is available. For example, this preference is useful at remote or otherwise self-contained installations of both a renewable power source and the load powered by that power source, such as at cell towers. However, the power generated by different types of power sources differs greatly in frequency behavior and in output impedance, especially in the case of renewable sources. These differences render it difficult to arrive at a power converter architecture that can optimally and efficiently convert power from this wide array of input power sources.
Regardless of the power source, it is important for protection circuitry to be provided near the input of the power converter, to protect the power converter circuitry from overcurrent events, and to ensure that faults within the power converter do not damage the power source. This protection circuitry commonly includes one or more relays, in combination with current limiting devices to reduce the “inrush” current at start up. But the differing attributes of the power generated by different power source types benefit from dedicated protection and inrush circuitry in power converters according to input power source type, or necessitate use of the most conservative components (e.g., “DC-rated” relays) to construct a power converter suitable for multiple types of power sources.